Daniel and Jorge Explain the UniverseCould we build a telescope that let us see what planets around other stars look like?
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Hey, Daniel, you know those awesome and amazing pictures of Earth that you see from space.
I love those earth as the blue Marble pictures. They are gorgeous.
Yeah, but I think they're also a little bit creepy.
Creepy because it gives you a sense for like how tiny we are, how insignificant we are in this vast ocean of space.
No, because it sort of makes me feel like, what if there's something out there taking a picture of us? You know, like I step outside, am I on camera?
Yeah?
What if they're like aliens on other planets watching us on the surface of the Earth.
Yeah, well, I guess I would really worry me, Except to I don't think I'm that interesting.
I don't know.
I bet everything that we do would be hilarious to aliens.
Live from Earth. It's Every Night Earth, the live action comedy show. Hi. I'm orgem a cartoonist and the creator of PhD comics.
Hi. I'm Daniel. I'm a particle physicist, and I'm always wondering if the aliens are watching.
Or hearing or listening. Right, they could be or feeling us I don't know.
Or sending emails to our podcast.
That's right. Any one of those emails you get every week every day could be from an alien, that's right.
I have no idea who's actually behind those emails. It could be a person, it could be a clever dog, it could be our interstellar listener.
Sorry, Bob from China could actually be Bob from Alpha Centauri. You never know. It could just be their handle.
If he's from Alpha Centauri and he's managed to email us, I wish he would send us some answers and not just some questions.
Wouldn't that be disappointing If you finally meet aliens and all they have is just more questions.
Well, that really just depends on who meets too. I mean, if they make it here, they got to know more about physics than we.
Do well anyways. Welcome to our podcast Daniel and Jorge Explain the Universe, a production of iHeartRadio.
In which we talk about all the incredible, beautiful, amazing, weird, bonkers phenomena that make up the universe around us and share with you our wonder and try to touch on the wonder that's inside you, the curiosity to understand the universe.
I'm right. We talk about all the amazing things to see from this little rock that we're sitting on called planet Earth, and we also like to talk about all the things we can quite see just yet, but that we may one day.
That's right. The journey of humanity and science has been one of ever reaching ability to see further and further into the universe. First we just looked up with our eyeballs. Then we build telescopes to reveal the moons of Jupiter and the farthest planets. Then we saw even further to discover that there were other galaxies out there in the universe. And now we have an incredible three D vision of a huge, vast reach of space. But there are questions that remain, what's out there, who's out there, what are they doing? Are they listening to this podcast.
Sorry, who or what is out there? Because who knows if aliens even go by? Who? Right? What's their pronoun? Not true?
Is that your first question? My first question is about physics. Your first question is what's your pronoun?
Well, yeah, that's kind of the standard these days.
That's true. Diplomacy will be important if we don't want to get eaten before we even get to ask physics questions.
I see, you want to choose how we get eaten. You know, you never know. But we do talk about aliens sometimes in this podcast, and it's something that you know, we talked about having skepticism about, and we've talked about whether it's possible that there are aliens out there. But I guess one thing we've never really touched on is the fact that if there are aliens out there, they probably come from a planet.
Yes, a planet, or a moon or some rocky body. But you know, again, it depends on sort of how you define aliens. If you define it to be some kind of life that's similar at all to ours, then yeah, you'll need some kind of environment that's similar hours But you know, you could imagine aliens living in energy streams inside suns or intergalactic media on very long time scales. The more science fiction you read, the more crazy ideas you need to think about.
Oh I see, huh, Well I guess yeah, I guess I'm thinking more of like aliens who live on planets. And so the question is, could we ever take a picture of these aliens and their planets and what's possible to see from other planets that are not in our solar system?
And it's crazy that we even think about this kind of question because remember it's only like twenty twenty five years ago that we figured out that there are other planets out there and that we could detect them, we could like measure them and prove that they exist. That's like a very recent discovery. You know. In the nineteen eighties, we had ideas we were pretty sure there were planets in other solar systems, but we've never actually seen one, and so it's pretty recent that this is like something we can grapple with at all. And so now of course we're getting greedy and we're wondering, like, well, you know, how well can we see them? Can we zoom in on these planets?
Yeah, So to the on the podcast, we'll be asking the question can we see the surface of exoplanets?
And right off the bat, I want to clarify something because I feel like a lot of the coverage of exoplanets, when they discover a new one, he usually says, you know, new Earth like planet discovered, and then in the article there's a picture of a nice ocean world with continents, whatever, And I think people get the impression that that that's a picture of that planet. But for some reason, space journalism usually features artists, blowney renditions instead of real data.
So I want you to impact there, Daniel in your statement, first of all, space journalism, man, what a fun title to have in your business card. I'm a space journalist, yeah, exactly, a space reporter.
Kudos to those people, But why do they keep featuring, you know, artists imagination over data. I have nothing against artists imagination, but it's not a stand in for actual knowledge.
I'll just put in my business card intrepid space reporter. Why not? But maybe this might not be a word that everyone who's listening has heard of you for exo planet, does that mean that it's like a X planet or you know, like a kitchen utensil type of planet. It just means a planet outside of our Solar system, right, That's why we put the word exo in front of it. It's like outside planets.
Yeah, exo just means in another Solar system, and so exoplanet just means a planet around another star. You know, we've seen in our Solar system there are eight or nine planets, depending on which side of that ridiculous argument you fall. But other solar systems are really far away, three, four, ten, a thousand light years away, and so the planets around those stars. Remember, planets are really small compared to stars, and so the planets around those stars are very difficult to even detect, not to mention, actually image or like zoom in on to see what's going on in that neighborhood.
Yeah, and like you said, we open toil about twenty thirty years ago. We only had an idea that there could be other planets out there, but we didn't really confirm or really have physical evidence that there existed other planets, Like it could have been that every star was seen in the night sky doesn't have any planets, and we are the only planets in the universe.
That's right. Just like we don't know whether we're alone in the universe. We didn't until recently know whether we were the only planets in the universe, which is kind of crazy, but you know, the universe is crazy sometimes, and you don't know if you're one of a kind, and the reason you're asking this question is because you're the only one around to ask it, or if you're one in a trillion. So far, the trend seems to be the one in a trillion direction. There are lots of galaxies, there are lots of stars. Now we know there are lots of planets. But you can't make assumptions. You can't just you know, artists' imagination your way to answers. You have to actually figure them out.
Yeah, And so now we know that there are a ton of planets out there, you know, not just like a few planets out there, but it's like almost every we know for sure, almost every star out there has probably a handful of planets, right.
Yeah, And every time we discover one of these planets, I wonder, like, wow, what does it look like it's going on over there? Yeah, And it's a fascinating question. And you know, we only recently saw close ups of the planets in our solar systems. We sent the the missions just in the last twenty thirty years to take close up images of Jupiter and Saturn, and then in the last few years of Pluto, you know, Pluto, until we sent new horizons to image, it was just like a little fuzzy dot in even the most powerful telescopes. Now we know it has that cool heart shape on it. But this is like a human need to visualize things, to see them close up.
Yeah, And so the question is if we are ever going to i don't know, study other exoplanets out there in the galaxy or in the universe, or you know, sort of get confirmation of what they look like, what will we need to do, Like do we need to send the satellite to take a picture or could we take a picture from here.
Yeah, it's a fascinating question. I would love to see these pictures of planets around other stars. And maybe we'll see like aliens spelling out messages for us or something sos like with rocks on the beach, send more pizza.
Maybe that's what the herd in Pluto is. Maybe it's a message from Plutonians right now that we're totally like, oh, that's cute. It's hard and there's distress, oh man.
And here we are making jokes about it. Man, we are heartless.
But anyways, as usual, we were curious to see how many people knew the sort of about exoplanets, and also whether or not we can see the surface of exoplanets, and so Daniel went out there into the wilds of the internet to ask this question.
Yes, So thank you to everybody who volunteered your time to answer speculative questions online and to hear your wild speculations on the podcast. If you'd like to participate in future listener questions, please just shoot us a message to questions at Daniel and Jorge dot com.
So think about it for a second. Do you think we can see the surface of other planets in the galaxy? Here's what people had to say.
I don't think we have any technology right now to see planets exoplanets from space.
That might depend what you mean by sea. I don't think we can see the surface of exoplanets.
I'd imagine you.
Need to get a spacecraft out there.
I'm not sure.
I think they might be too far away. I don't think we can actually physically see any surfaces of exoplanets. As I don't think we've got a telescope that does anyone near them?
Yes, definitely, I would say no, I don't think we can. As far as I understand, we can't really see exoplanets at all. We can just detect them, all right. Not a lot of optimism here for taking a picture. Everyone's like no, only a couple of yeses.
Yeah, pretty much universally shot down because it seems ridiculous, right, Like we said, the planets in our own Solar system are so far away that it's hard to image. So how could you possibly imagine taking a picture of the surface of planets super far away around other stars? It sounds like ridiculous science fiction.
Yeah, it's like trying too. I guess. Take a picture of a marble that's across the world. Maybe I don't know if the scale works out, but it sounds like that. It's not hard.
Yeah, a marble across the world that's next to a really bright light.
Yeah, next to a lighthouse.
I've heard that, Yeah exactly, And now you want to see, like, yeah, but is it a blue marble? Is it a green marble? Are there tiny little bugs walking on the surface of that marble? People want to.
Know what's the pattern of air molecules around that little marble.
Yeah, we want to predict the weather on other planets, even though we can't e from predict the weather here on Earth.
All right, well, step us through this, I guess. Maybe let's start with the basics, like how do we know where there are other planets out there? And how many of they are? Like, what do we know? How do we find other planets outside of our sources?
Right?
Well, the first thing to understand is that seeing those other planets directly is really really hard, which is why this whole topic is so ambitious and maybe ridiculous. And the way that we know that those planets exist is not by seeing them, right, those pictures you see in the science articles are not pictures of those planets. They're totally made up. Instead, all we can do is see the effect of those planets on the stars that they are orbiting. Like, we don't see anything really directly about the planet. We see how it impacts the star and sort of in two different ways.
Yeah, it's kind of like that listener who said it kind of depends on what you mean by seeing another planet, right, Like if we only see its effects on other things. Is that really count as seeing or not?
Yeah, And we got into that whole rabbit hole when we talked about the black hole, like are we seeing the black hole? Are we seeing the gas around the black hole?
Etc.
Well, in this case, what we're seeing is two different effects on the star. One is the wabble of the star. So when a planet orbits a star, it's orbiting because the star is pulling on it with its gravity. But there's a reverse effect also, the planet is pulling on the star with its gravity, so the two are sort of tugging on each other. And of course the planet is much smaller, so it moves a lot more, but the star also moves. And if you take really careful pictures of the star, you can detect this wobble because it's periodic. Right as the planet goes around, it wobbles steadily. It's not like a random jiggle. So if you watch it over a period of time, you can see the star moving and that tells you how massive the planet is, whether there's a planet there, and how massive it is.
Right, you measure the wiggle in the star and you do it through like the Doppler effect. Right when it wiggles towards us, then the light shifts a certain color, and when it's wiggling away from us, it's just another color. And so physicist astronomers can actually detect that in a little bit of light that comes from that star, you can actually detect that wiggle, which is amazing.
Which is amazing, right, Like everything that the astronomers are doing here is sort of aspirational. Like twenty years beforehand, people would have scoffed it, like that's impossible, But now we're doing it, and that's the kind of thing that motivates you to think, like, well, what do we think now might be impossible that in twenty years we'll have figured out and then we'll be thinking about the next thing. Right, science and technology moves exponentially, so it's good to think big.
Yeah.
Anyway, So that's the first method. The second one is the brightness method, and that's if the planet happens to pass between us and the star, then it partially blocks the light from that star. It's like a fly, you know, flying in front of a lighthouse. You can detect a very small dip and the amount of light that comes from the lighthouse, and again it's periodic. You can see it regularly, so you build this up over many, many orbits and you can get evidence that it's there.
Right, And it's kind of a very specific dip in the light. Right, like little fly fly in front of a lighthouse. You would see the light from the lighthouse sort of like a fly eclipse almost but only a little bit. You can see the light sort of dip stay even as the fly makes it across the lighthouse surface, and then pop back up when the fly leaves the kind of the brightness of the lighthouse. And you're looking for these very specific kind of dips in the light.
That's right. Not every variation in a star's brightness is due to a planet. You're exactly right. It has to be very consistent with the orbit of an object around the star, and it would make that pattern. In fact, there was that star recently we saw where there was a very inconsistent dip in the light around the star and people thought, oh, maybe that's Aliens building some huge megastructure and it's only half finished and they haven't finished the parking lot on that interstellar mall, and that's why the light is deeping in this weird way.
They just went straight for the aliens. They're like, there's an unusual variation aliens.
Yeah, and so we've seen this on lots and lots of planets now. But you know, it requires the planet to be in the right plane, like the plane of these solar systems, the plane around which the planets are orbiting the star is randomly organized in the galaxy, and so it has to be aligned just right so the planet actually goes in front of its star. So not every big planet out there can we even see with this brightness method, right.
And this is sort of historical, right, because I think they started detecting planets with the wobble method, I think, and then they sort of switched to the brightness method of looking at the dips in the light, and that for the explosion of exoplanets really, or the discovery of exoplanets happened because then we were able with the Hubble telescope to just like survey a bunch of stores at the same time and look for these dips in brightness. Yeah.
And now we have dedicated telescopes just to do this, just to find planets through the brightness method. So it's much more powerful now that we have the technology and now we've seen thousands of thousands of planets, like we haven't seen them in the sense we don't have an image of them, but to resort to artists if we want to poof up our science journalism a little bit. But we have evidence that they exist. We know their mass and we know their radius, and so we know something about them, but we don't have images of them. We don't know necessarily what they look like.
We sort of feel like we know we've seen their shadow kind of right. We've seen how they block the light, and that tells us a lot about like the mass and the orbit. We don't have a picture of a surface yet.
Yeah, that's a great analogy because we know from the shadow that it exists. It must be there because it's blocking the light. It's having this impact on the light's source. But it's not the same thing as seeing the object itself.
All right, Well, let's get into the problem of taking a picture of the surface and whether or not it's even possible. But first let's take a quick break.
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All right, we're talking about taking pictures of exoplanets planets outside of our Solar system, and whether or not those pictures you see in science fiction or in some news reports is to be believed. So this is really hard problem to actually see the surface. But actually I was just kind of thinking back, isn't there do we have a picture sort of of some exoplanets orbiting around a star, like I have a memory of some of like an image of some blobs around a bigger blob which is the Sun.
Well, the thing that's important to remember, though, is that it's theoretically possible. Like what happens to a photon which comes off of some exoplanet, some planet really far away, The light from its star is hit it and then it's come out into space. And we know obviously that happens. You can see the Earth from space, right, it doesn't glow on its own, it's reflecting life from its sun. But think about what happens to a photon that hits that exoplanet and flies off into space. There's nothing that prevents it from getting to Earth. Right, it can fly from the surface of that planet, carrying information about the alien's lunch or whatever, and come all the way to Earth and hit your eyeballs. No theoretical problem to that.
Just like it's theoretically possible to see a marvel halfway across the world if he somehow had a good enough eye.
Exactly. The problem is that you don't get very many of those photons. Right, You get one photon from that alien's lunch, But because the planet is so far away, most of the photons go in other directions, and those photons spread out, and as you get further and further away, the density of those photons drops like one over the distance square. I think about the surface of a sphere that surrounds that The area of that surface of the sphere grows like the radius squared, and so by the time it gets here, you just have very few photons. So really it's a question of like gathering enough light. The light is getting here, you just need to gather enough of it and separate it out from any other light that might be overpowering it or confusing you. And as you were saying earlier, there are a very small handful of these things where we have seen the planet directly. I mean, we have a few pictures where the planet is far enough from the star and big enough to reflect enough light that we can see that it's there. But that only works for a very few exoplanets, and we've seen thousands of them the other ways. And for the ones where we can directly image them, it's not very satisfying. It's not seeing the surface of the exoplanet. It's just like one pixel. It doesn't tell us if it's an ocean world or if there are forests or just dust. We really need a lot more magnification to see the features, to see the surface of the planet.
Right, because I guess you know, it's kind of like the picture of Earth from the moon. You know, we can take a picture of the Earth from the moon, but then you could even go further, and technically you could still take a picture if you had kind of a big enough zoom lens.
Yeah, exactly. And you can imagine like taking a picture of the Earth from Pluto right, Like you've seen those pictures of satellites that are flying out in the outer reach of the Solar System, the Earth looks like a tiny dot. All the information is still there when you went outside and you waved up at the sky. The information from those photons is still out there in space, but it's spread out really far, and so the photon's density is very low. So you would need to either gather information for a long time or a really big lens. Like somebody did the calculation and discovered if you wanted to take the picture of another planet around another star, you'd need a telescope that's like one hundred kilometers wide, and you'd need to gather light for like ten thousand years.
Wow. That would not fit in my iPhone for sure, or my lifespan.
You know that pause when you press that take the picture button and it actually collects the light and takes the picture, and then you hear that click sound. Imagine if that pause is ten thousand years, like, all right, take the picture, they'll move, smile.
Exactly and hold it so that's how much it would take. But you know, I feel like we have telescopes that like gather one photon at a time. You know, couldn't we make use of every photon that comes in and kind of reconstruct a hazy picture.
Yeah, but you know, you could imagine building a telescope that's one hundred kilometers wide, even if it's not actually physically one hundred kilometers wide, by assembling different telescopes that are like around the Earth, et cetera, et cetera. But you still have to gather light for a very very long time because there just aren't that many photons. I mean, we're talking about a very small object that's not even that bright, and it's really really far away, so the numbers are really working against you. But in principle, those photons are there. So if you develop a big enough telescope or run it for long enough, then hey, maybe it's possible. So that's the nexus of the idea. That's the technical challenge that this problem is facing, Right, It's.
Just that it's really small and so it's really faint, yeah, and it's super far away exactly all right, Well, then how could we possibly ever see the surface of these other planets.
Well, the idea is literally build as big a telescope as possible, and because that's the only way you can overcome these tiny numbers is to have a massive telescope. And you know, we can't build something that's like the size of the Earth. So the idea is to use things that are already there. To use the Earth or the Sun, especially as a lens, because remember, the Sun is a big ball of stuff, and stuff has gravity, and gravity bends light, and so a big ball of stuff can act as a huge lens. And we've seen this in the sky already. If you google gravitational lensing, you can see these amazing pictures where we have some blob of dark matter and in the background way behind it is a galaxy and the life from that galaxy is distorted by the dark matter acting as a gravitational lens.
Right. Yeah, we could use the Sun as our zoom lens. Yeah, is that kind of the except that it's on fire.
Except that it's on fire, which you know causes some problems. Usually that's not what you want in your telescope, but.
In this case, usually you don't want it to be too hot to handle.
Yeah, Yeah, and so we're thinking, if you're going to build a telescope using some big massive object, use the biggest thing nearby, and the Sun by far is the biggest blob of mass.
But you were saying you need about I guess you need one hundred kilometer wide lens, but over ten thousand years. I was just wondering, like if you use you could use the Moon or something.
Yeah, the Moon just wouldn't be big enough. The idea is to use the Sun because it gathers a lot of light, Like it's so strong gravitationally that it's pulling photons nearby and focusing them. And so you get a factor of one hundred billion magnification if you use the Sun as a lens, which is a pretty big number.
Right, what was the number again? One hundred billion, one hundred billion, ten to the eleven. Wow, that's a lot of zeros. It's a lot of zeros for the X. Yeah, and so telescope.
And so the idea is you have your planet which you want image, which is really really far away, and then between the planet and you you put the Sun. So then the Sun bends a bunch of the photons which are flying towards our solar system, but which otherwise would not have hit Earth. Now get all bent together to some focal point, some focal point on the other side of the Sun where you can gather all these photons together. So it's like you're capturing a huge number of photons which otherwise would have just keep flying apart, and you're bending them together into one place so you can gather them together. That's essentially how the magnification works.
Oh, you need to put your camera, your sensor pretty far away from the Sun. You're saying, way past Pluto.
Way past Pluto. Yeah, this thing would be sixty billion miles from the Sun. Say, yeah, you have the exoplanet, which is like light years away, and then you have the Sun. Then you have the focal point, which is on the other side of the Sun from the exoplanet. But yeah, it's sixteen times as far away from the Sun as Pluto.
Wow, have we ever gone out that far?
We have not far.
No.
Voyager one is a thing that's gone the furthest the man made object that's deepest in space, and it's only gone thirteen billion miles, and so this thing would need to be out there sixty billion miles and you know, Voyager one's been going for forty years, so there are a lot of technical hurdles to making this work.
Just to take a picture. Yeah, I say, artist, do it, Daniel, use your imagination. Sounds cheaper.
They should draw more aliens. Then, if you're going to let an artist do it, then let him run wild. But I just love the you know, the scale of this idea, the hubris, the like, you know, let's use the sun to take a picture. I just love it.
But how would you I guess block the you need to block the light from the Sun and then gather the other like coming from around the sun.
Yeah, because you can't see the photons that actually hit the sun, right, the sun is not transparent, but you're seeing all the photons that sort of skim the Sun. They go near the Sun and then get bent towards your camera, and your camera is some satellites, it's like super deep in space.
Right.
But if you do this, there's a lot of information there. In principle they've crunched the numbers. You can take a picture of that planet that's like megapixel of real for real. Every pixel that you capture in your satellite would be equivalent to like twenty five square kilometers on the surface of that.
Planet, which is not small, which is nothing.
It's pretty small. You could see, you know, oceans, you could see continents. You probably couldn't see aliens spelling out sos on the beach. They're really really they've had a lot of pizza. But yeah, you could see the shape. You could see like, you know, even maybe mega structures, right, you could see stuff on the surface maybe yeah, yeah, they have like a massive space infrastructure. You might even be able to see that. So that would be incredible. I mean, imagine seeing that picture. Imagine being those scientists building this technology, pressing the button, and then you know, a few years later you get the result and you get to actually see this, like, Wow, what a moment that would be for humanity.
Wow, So let's do it? Why don't we do? We do it? Sounds like, doesn't it sounds like you just have to build a satellite's what's the technical or financial purdle here?
Well? Number one is that it'll take a long time to get there, right, So we've spent forty years getting Voyager one out thirteen billion miles. So we don't want this to happen in one hundred and sixty years. Right, we need to somehow get there faster.
Right, But Voyager doesn't have like booster rockets or anything, does it. Don't we have technology now to get there faster?
Yeah, exactly. Voyager is not a race car, right. We have ways and ideas to make things go faster. And the idea is instead of sending one big satellite, which is sort of hard to power, sending a bunch of mc gross satellites, like streams of pearls of satellites, and each one powered by a solar sale. A solar sale is not actually like a jet engine of any kind. It just captures the energy of the Sun's own light and sails on it. It captures those photons and it uses that to pull itself along.
All right, Well it sounds pretty cool, and I say, let's do it, Daniel. Let's just let me hop on the phone here with NASA, and I'll let him know I approve of this planet.
That's what they've been waiting for. Absolutely.
But let's talk about maybe what we would actually see in these other planets if we ever took a picture of him. But first, let's take a quick break.
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Hi, I'm David Eagleman from the podcast Inner Cosmos, which recently hit the number one science podcast in America. I mean neuroscientists at Stanford, and I've spent my career exploring the three pound universe in our heads. We're looking at a whole new series of episodes this season to understand what, why, and how our lives look the way they do. Why does your memory drift so much? Why is it so hard to keep a secret, When should you not trust your intuition? Why do brains so easily fall for magic tricks? And why do they love conspiracy theories?
I'm hitting these questions and hundreds.
More because the more we know about what's running under the hood, better we can steer our lives.
Join me weekly to explore the relationship.
Between your brain and your life by digging into unexpected questions. Listen to Inner Cosmos with David Eagleman on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts.
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All right, Daniels, So you have a plan for taking pictures of planets outside of the galaxy, and people have crunched the numbers and it is kind of possible if you put a satellite out pass way past Pluto, you could use our sun as the lens and actually take like high resolution pictures of planets in other stars.
Yeah, yeah, exactly. So what's the hurdle here. The hurdle is really just making it work and getting the money. We think we know how to do it. There's just a lot of technical issues to overcome. And this is something that NASA is actually supportive of. This is not just like crazy bonkers idea out there on the internet, you know, in some reddit thread. This is a proposal that's into NASA, that's moving along the stages that could actually be approved, and they're taking these challenges seriously. And the challenges are basically like how to get out there quickly, how to point this thing accurately enough, how to build a big enough satellite because the image is going to be still really huge and you want to sample it night. How to control this thing when it's really far away. Also, how to pick which planet to look at, because one issue is you build this thing, you send it to one place in space. You can only look at one planet. You can't like turn this thing to look at a totally new planet.
We can't turn it.
We can't turn it because the location of an image for an exoplanet is in a civic spot in space. And then if you want to image another exoplanet, you have to go to where that image is right the image is always on the other side of the Sun. You can't move the Sun so you have to move where your camera is, and those locations are really really far apart, and so basically you have to pick before you go. You just send your camera out there and you have a telescope dedicated to one planet.
Oh really, I would think that there are so many stars out there that we would have our thousands of exoplanets that we know about and could focus on. Wouldn't this phase be literate images of these planets?
Yeah, but you have to be really precise about where you're imaging, and so in order to change the target that you're looking at, you need to be able to move laterally. And most of these spacecraft that we're sending are only going to be able to move radially, like we're sending them out there, and they're actually going to be traveling outwards as they take an image. They're not going to stop. It's not like they get out there to the focal point and then they just stop. They get out there, they start taking images when they get to the focal point, but it's more actually of a focal line, and as you move along that line you get further from the Sun. You take pictures of different parts of the planet. So you have to integrate over many years as you move further and further away. So it's like a one shot deal.
What cann't we build a spacecraft that stands still and takes the picture.
Yeah, that would be much more complicated. You'd have to be able to stop. These things are going to be moving really really fast by the time they get out there. To get out there at a reasonable amount of time, you need to accelerate to a very high speed, and then to stop requires as much energy. But you no longer have access to the solar energy in order to slow down, and we only know how to build solar sales to sort of speed up slowing down, it's a whole different problem.
You need a solar parachute.
Or something, a solar break.
Yeah, all right, Yeah, you were telling me that these things would need to be would take twenty five years to get there, and they would need to be three hundred times more accurate than hubble, which is pretty kind of our state of the art kind.
Of Yeah, exactly, because you have to point very precisely, like the light is going to be coming from that planet bending around the Sun, making this Einstein ring. It gets distributed all the way around the Sun. Then you have to point at exactly the right spot in the Einstein Ring. And even still, even though you have all this magnification from the Sun, you still have to spend a lot of time building up the image. So you want to keep your camera pointed at exactly essentially the same target pixel for weeks and weeks and weeks or months in order to gather in a photon to actually see what's there.
Does it sounding less appealing by the minute here, Daniel, I'm like, how much do I want to see a picture of another planet?
Well, you mean, it's just engineering trouble. You want to? You want to? I mean I want to enough for both of us, trust me.
But if we pick one planet and we send a satellite and it's a boring planet.
That's a real concern.
You know.
If we have four thousand plants to pick from, it could be that like one hundred of them have amazing superstructures an alien life on them, and we just pick one that's like dust and rubble, and it's like yawn, And that was one hundred billion dollars and thirty years of work.
Oh my goodness, Let's send four thousand satellites. Then that's obviously the solution.
That is a great idea. I'm loving that idea.
Can I how people take pictures these days with their phone? You know, they don't just take one picture. They go like and then later you pick the one where nobody's blinking.
Yeah, I'm pretty sure they do that because those pictures are free, and if each one costs a hundred billion dollars, people might press that button with a little more thought.
Yeah, they might think about it a little bit more for sure.
Yeah. And you know, we think we know how to solve this problem, but there are still a lot of technical issues. Like we are seeing faint photons coming through the corona of the sun essentially, and you have to pick out these photons from that corona. It's not an easy job to increase the signal to noise ratio to the point and this is actually gonna be doable.
We need a pretty good set of sunglasses or pretty solid thumb to put in front of the sun.
Absolutely you do. In addition, this thing has to basically control itself. It's going to be so far away from the Earth that we can't like send messages. You can't drive this thing with a joystick. It's going to take four days for messages from Earth to get to our camera that's out there in the solar focal point, and so basically has to organize itself. It has to be basically AI power.
My goodness, the first AI photographer.
That's right. How do we know it's not just doing deep fakes and sending us images? It's made up on the Internet.
That's right. The alien could gain a sentience, and then it'd be like, this is too much work. If I send them a born planet, they're going to fire me. I'll just deep fake a fun, cool planet with aliens in it.
Yep, and then we'll get all excited. We'll send an interstellar ship towards the direction of that planet, and then only in a thousand years where we discover that we relied to. That sounds like an awesome plot for a science or novel. A little bit of a letdown at the end, but sounds interesting.
But you're right.
We could take a picture of this planet and we could discover nothing, or it could be fascinating, or it could be like confusing and fuzzy. Right, we're going to see a picture of this planet. We're not going to necessarily be able to tell what we want. We're not going to see literal aliens walking around on the surface. At twenty five square kilometers per pixel. We might just be able to make out fuzzy details. I mean, remember what it was like when we first got pictures of the surface of Mars from Earth. People thought they saw faces and canals, and there's lots of excitement, of course, all of which was bubb gus.
Why they did see a face, didn't they.
Yeah, they saw a face, but it was just a mountain shape where that happened to have a shadow that looked like a face.
Right, No, I mean, isn't there a big smiley face on the surface of Mars.
Or I'm not sure if that was an artist impression or actual data.
All right, well, it sounds like it's going to be pretty difficult to get a picture. Can we send a satellite to another planet, Daniel and take a picture closer?
We certainly could, and that would be awesome, but it would take a zillion years to get there.
Billion. I guess what's the closest exoplanet that we know about it?
Yeah, the closest exoplanets are you know, in the five to ten light year distance, and that's pretty far away. You know, if you built Hubble, for example, and send it that far away, you couldn't send it at really high speeds very easily. It can't tolerate a lot of acceleration, so it would take a long time to get there and then take those pictures and send them back. I mean, hey, that also sounds like a good idea. Let's do both, Let's do it all, let's do it all. I mean, we're spending trillions on everything these days, so why not one hundred billion to see pictures of alien.
Yeah, well, it would take maybe like a couple of dozen years, you think, or hundreds of years to go and take a picture of another planet.
How long it takes to get out there depends a lot on the propulsion you use, and for your very expensive, important telescope, you probably want gentle acceleration, but you also wanted to get going pretty fast. So I think the best option is to build like a solar sale the size of Texas, and that might be be able to get your telescope up to like ten percent of the speed of light, and it would still take like, you know, fifty to one hundred years to get there. But hey, yeah, that sounds like.
A great idea. You're like, this one is Daniel approved? Call NASA, let me start a ready tread here to tell me we approve.
I only have enthusiasm. I have no responsibility, and that's why I have no authority also to make these decisions.
Some other two are linked, but not quite sure.
Why exactly exactly, No, but I think it's a fascinating question. I think it's sort of the next generation, you know, the next frontier and understanding what's out there in the universe is to get these close up pictures of what's going on. And so I'm looking forward to it. I'm hoping that this kind of thing happens and that we press the button and we see the picture, and then I get to see the picture, a literal picture, not an artist impression, of what's happening on these plans, right.
You know, it feels like a basic human curiosity, you know, to see pictures, to see like actual photographs of something, not just like the blip in the light or you know, the gravitational effects or something. You know, there's something about our human brain that we just we need to see it.
Yeah, and you know it makes you wonder if there are alien civilizations out there that already have this technology. If we're on the verge of it, and we've only been around for a few tens of thousands of years as a civilization, certainly somebody else has figured this out, and somebody else may have even put a picture of Earth up on their walls someway out there in the.
Unit, and then tragically those swipe left. They they're like, oh, look at this blue planet and it looks kind of boring, or let's keep.
Going, yeah, or maybe that's good.
Right, yeah, I'll look at this blue planet. Doesn't look delicious. Let's keep on. Let's keep on.
What do you want for lunch today? You guys feeling like Earth or you know some other planet?
That's right, everybody look as unappealing as possible. I think we're on our way there.
Then that's right. I do my best not to look delicious every day.
All right, Well, we hope you enjoyed that, and then hope you look at the night sky, or look at the sky out there and wonder what do other planets look like. Do they look like Earth or Mars, or Venus or Jupiter or maybe something completely different.
That's right, And remember that the technologies. The capabilities that we are scoffing at today are things that scientists and engineers are imagining and working on to make possible for tomorrow, and humanity's ability to see what's out there in the universe, to understand what's in this crazy bonker's cosmos, and to peel back layers of reality to penetrate what's really happening seems unlimitable, and so hopefully our children and our children's children will know so much more about the way the universe actually looks.
H Yeah, and they won't have to use their imagination.
That's right, and maybe it'll even be cheap by then. There'll be an app for that in five hundred years, right.
That's right. You can swipe left, right, up and down see any planet you like. Well, thanks for joining us, See you next time.
Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of iHeartRadio. For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. When you pop a piece of cheese into your mouth, you're probably not thinking about the environmental impact, but the people in the dairy industry are. That's why they're working hard every day to find new ways to reduce waste, conserve natural resources, and drive down greenhouse gas emissions. House US dairy tackling greenhouse gases. Many farms use anaerobic digestors to turn the methane from manure into renewable energy that can power farms, towns, and electric cars. Visit you as dairy dot com last Sustainability to learn more.
Hi, I'm David Eagleman from the podcast Inner Cosmos, which recently hit the number one science podcast in America. I mean neuroscientists at Stanford and I've spent my career exploring the three pound universe in our heads.
Join me weekly to explore the relationship.
Between your brain and your life, because the more we know about what's running under the hood, that.
Or we can steer our lives.
Listen to Inner Cosmos with David Eagleman on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts.
Parents looking for a screen free, fun and engaging way to teach your kids the Bible. As a mom, I was looking for the same thing, so I created Kids' Bible Storys podcast. Thousands of families are raving about it, and kids actually request to listen. With captivating sound effects, voices, and an apply section at the end to spark meaningful conversations, it's a hit with both kids and parents. Listen to Kids' Bible Stoics podcast on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts.
